A set of prototype measures has been developed to measure students' understanding of content areas. Although the starting point has been history, the project has explored the use of a common model for assessment in geography and science as well. These prototypes are intended to provide models for users with assessment requirements who do not have the resources or desire to start the design process from scratch. Derived from a perspective that understanding requires the engagement of the learner with specific detailed content, each example uses concrete textual or graphical materials as part of its stimulus materials. The student's job is to explain, in writing, the meaning of the materials. Specifications are given for the history text materials, the history prior knowledge measure, and the history essay task, as well as the geography and science tasks. To date, the following nine complete sets of assessments that have been developed and tested are listed in separate appendixes with their essay scoring rubrics: (1) Revolutionary War (Henry-Inglis); (2) Revolutionary War (Paine-Inglis); (3) Civil War; (4) Depression; (5) General Immigration; (6) Asian Immigration; (7) Geography; (8) Chemistry; (9) Baking Task; and (10) Essay scoring rubric for history, geography, and science. Ten tables summarize test specifications. (SLD)